First of all, I set the Source format to "no$GBA" and the target to "M3 (dat)" this didn't work. So, after finding this, I changed the save setting to RAW, and tried again, using the suggested settings, Source as Supercard One, and the target as M3 again. Still didn't work.

The game I am trying to convert is a Pokemon save though, and it seems they don't work. Which is a shame.